ObjectiveTo investigate the effects of mitotically-associated long non-coding RNA （lncRNA MANCR） on the proliferation，migration， and epithelial mesenchymal transition （EMT） of gastric cancer （GC） cells by regulating the microRNA-50-5p （miR-150-5p）/non-metastatic melanoprotein B （GPNMB） axis.MethodsThe mRNA expressions of lncRNA MANCR，miR-150-5p， and GPNMB in 42 cases of GC tissue and adjacent tissue resected during surgery in the First Hospital of Hebei Medical University from June 2022 to September 2023 were detected by Real-time PCR. Human gastric mucosal epithelial cells GES-1 and human GC cells BGC-823 were cultured in vitro， and their lncRNA MANCR expression was detected. BGC-823 cells were randomly separated into control group （routine culture），sh-NC group （with sh-NC transfected），sh-MANCR group （with sh-MANCR transfected），sh-MANCR + anti-NC group （with sh-MANCR and anti-NC both transfected），and sh-MANCR + anti-miR-150-5p group （with sh-MANCR and anti-miR-150-5p both transfected）. The mRNA expressions of lncRNA MANCR，miR-150-5p， and GPNMB in the BGC-823 cells of all groups were analyzed. EdU staining was used to detect the proliferation of BGC-823 cells. Transwell assay was used to detect the migration and invasion of BGC-823 cells. The expressions of EMT-related proteins E-cadherin，N-cadherin，Vimentin， and GPNMB were detected by Western blot. The interactions between lncRNA MANCR and miR-150-5p and between miR-150-5p and GPNMB were analyzed by dual luciferase reporter assay.ResultsThe mRNA expressions of lncRNA MANCR and GPNMB in GC tissue were higher than those in adjacent tissue，and the expression of miR-150-5p was lower than that in adjacent tissue （P<0.05）. Compared with that in GES-1，lncRNA MANCR expression in BGC-823 cells was increased （P<0.05）. Compared with those in the sh-NC group and control group，the EdU-positive cell rate，migration number，invasion number，the mRNA expressions of lncRNA MANCR and GPNMB， and the expressions of protein，N-cadherin protein， and Vimentin protein in the BGC-823 cells in the sh-MANCR group were lower ，and the protein expressions of miR-150-5p and E-cadherin were higher （P<0.05）. Compared with those in the sh-MANCR group and the sh-MANCR + anti-NC group，the protein expressions of miR-150-5p and E-cadherin in the sh-MANCR + anti-miR-150-5p group were decreased. The EdU-positive cell rate，migration number，invasion number，mRNA expressions of GPNMB， and expressions of protein，N-cadherin protein， and Vimentin protein were increased （P<0.05）. lncRNA MANCR could target the negative regulation of miR-150-5p，and miR-150-5p could target the negative regulation of GPNMB.ConclusionKnockout of lncRNA MANCR can inhibit the proliferation，migration， and EMT of GC cells by regulating the miR-150-5p/GPNMB axis.

mitotically-associated long non-coding RNA;microRNA-50-5p;non-metastatic melanoprotein B;gastric cancer;proliferation;migration;epithelial mesenchymal transition